[Dbix-class] DBIx::Class::Loader 0.18 released

[Brandon Black]

On 2/4/06, Brandon Black <blblack at gmail.com> wrote:
> On 2/4/06, Alex Kavanagh <alex at tinwood.homelinux.org> wrote:
> > Brandon Black wrote:
> > > DBIx-Class-Schema-Loader is now at version 0.01002 on CPAN, and it
> > > seems like it should work for most people.  Please give it a shot.
> > > The transition could be rough for some, as some Loader users are
> > > probably using Loader-isms in their DBIx::Class code that will need to
> > > be changed to Schema-isms.  By 0.02 I expect it to be fairly stable,
> > > other than future feature additions for obtaining better metadata and
> > > building smarter relationships.
> >
> > Okay, I'd like to try to switch.  I'm using it with Catalyst which
> > I've only just started using and therefore I don't really know whether
> > I'm using bad DBIx::Class usage habits.
> >
> > Is there a tutorial or some info on how to switch from D::C::L to
> > D::C::S::L ??
> >
>
> No, there's no such tutorial at this time, although perhaps there
> should be a guide of sorts.
>
> The problem can really be divided into two parts.  Firstly, even with
> older versions of DBIx::Class and DBIx::Class::Loader, some people are
> unwittingly using loader-specific methods and not realizing it.  For
> instance, I was using My::DB->table('foo_table')->search() all over
> the place in my code.  That usage of ->table('foo_table') is a
> Loader-ism.  Even at the time, converting off of ::Loader to a
> manually-defined DBIx::Class would have meant eliminating that usage.
>
> Secondly, there's the differences between the old DB-based way of
> using DBIx::Class, and the new Schema way.  The old DB-way still works
> for manual users of DBIx::Class, or users of DBIx::Class::Loader
> against newer DBIx::Class, but I don't believe it quite works for
> using ::Schema::Loader, seeing as the entire definition is done in the
> Schema way, not the DB way.
>
> In the DB way, it was possible to do things like
> My::DB::FooTable->search();
>
> Whereas in the Schema way, this should be written:
> $myschema->resultset('foo_table')->search();
>
> Even in pre-0.05 DBIx::Class, the first method using statically
> defined Table-class names was unwise, but it just worked.  It still
> works if your database and table classes are defined the DB-way, just
> not if they're defined in the newer/better Schema way of doing things.
>  The new Schema::Loader defines them in the Schema way, so...
>
> Someone who was using DBIx::Class::Loader and then usage patterns like
> MyDB->table('foo')->search()
>
> or
> MyDB::Foo->search()
>
> will need to switch to:
> $myschema->resultset('foo')->search()
>
> Technically you can also do:
> My::Schema->resultset('foo')->search() on a connected schema-class,
> but it's probably unwise as you'll have to go back and make them
> object methods if you ever want to use multiple connections at the
> same time within the same perl execution environment (for instance, if
> this code is in a mod_perl app, and multiple instances of this app
> with seperate databases are expected to run in a single apache
> server).
>
> There are also loader-specific mechanisms in a Schema generated by
> DBIx::Class::Schema::Loader, which should be avoided if you ever might
> move off of Schema::Loader to manually defining your Schema.  However,
> it's rather difficult to not realize you're using them, as they are
> all accessed via $myschema->loader, like $myschema->loader->tables;
> $myschema->loader->monikers; etc.
>
> When/if you convert off od Schema::Loader, $myschema->loader is the
> only thing that will cease to exist.  Everything else should work the
> same regardless of whether you're using ::Schema::Loader or a
> manually-defined Schema.
>

That posting was a bit hasty, as the examples are poor.  The usages
shown of ->resultset() should look more like ->resultset('FooTable'),
as the monikers tend to be uppercased in their first letters and not
contain underscores.

-- Brandon